Over the past forty years, businesses have sought to maximize efficiency by using various devices to automate data entry. In the important area of inventory management, in particular, the symbol reading device (e.g., barcode reader, barcode scanner or RFID reader) has greatly reduced the time and errors inherent to manual data entry. Symbol reading devices are often employed to decode barcodes. A barcode is a machine-readable representation of information in graphic format. Traditionally, a barcode is a series of parallel bars and spaces of varying widths (e.g., a linear barcode or 1D barcode). More recently, there has been an increase in the use of alternatives to the linear barcode, for example matrix codes (e.g., 2D barcodes, QR Code, Aztec Code, Data Matrix) and Optical Character Recognition (OCR) have enjoyed increasing popularity as the technology advances. As used herein, the terms barcode and code symbol are intended in their broadest sense to include linear barcodes, matrix barcodes, and OCR-enabled labels. Barcode readers (e.g., optical readers) tend to fall into one of three categories: wand readers, laser scan engine barcode readers, and image sensor based barcode readers.
Wand readers generally comprise a single light source and single photodetector housed in a pen shaped housing. A user drags the wand reader across a decodable symbol (e.g., a barcode) and a signal is generated representative of the bar space pattern of the barcode.
Laser scan engine based barcode readers comprise a laser diode assembly generating a laser light beam and a moving mirror for sweeping the laser light beam across a decodable symbol, wherein a signal is generated corresponding to the decodable symbol.
Image sensor based barcode readers comprise multi element image sensors such as CID, CMOS, or CCD image sensors and an imaging optic for focusing an image onto the image sensor. In the operation of an image sensor based barcode reader, an image of a decodable symbol is focused on an image sensor and a signal is generated corresponding to the signal. Image sensor elements may be arrayed in a line or in a rectangular matrix or area. Area image sensors capture a digital picture and use software algorithms to find and decode one or more symbols.
Users of laser scanner engine based barcode readers have been switching in increasing numbers to image sensor based barcode readers. Image sensor based barcode readers are more durable and offer additional features relative to laser scan engine based barcode readers. Features and functions which have been incorporated into image sensor based barcode readers involve image processing.
Exemplary optical readers are described in U.S. Pat. No. 6,298,176; U.S. Pat. No. 7,159,783; and U.S. Pat. No. 7,413,127; each of which is hereby incorporated by reference in its entirety.
Recently, the widespread availability of mobile devices such as smartphones and tablet computers, and their continually improving functionality, has led businesses and consumers alike to employ these mobile devices as code symbol readers. In this regard, smartphones and tablet computers typically have an internal video camera that can be employed for image scanning.
Unlike conventional symbol reading devices, which typically have an aiming indicator that can be projected onto a code symbol (e.g., barcode, linear barcode, matrix barcode, letter strings, number strings) with an LED or laser, smartphones and tablet computers typically lack a built-in aiming indicator. Accordingly, decoding software for smartphones and tablet computers typically utilizes a user interface with a real-time display from the internal video camera to aid users in aiming at the code symbol. A continuous graphic pattern is typically overlaid on the real-time display to further aid with aiming. For example, a horizontal line that mimics a laser scan line may be painted on the display, so that a user can orient the device so that the horizontal line cuts through the barcode. Alternatively, a graphic pattern delimiting a reduced region of interest may be painted on the display, so that a user can position the barcode within the region of interest. In addition to lacking a satisfactory way to direct the aim of the scanning operation of the mobile device, mobile devices also lack an intuitive trigger to activate the scanning operation. Typically, scanning is initiated whenever a readable barcode enters the mobile device's field of view in a proper orientation. When multiple barcodes are in the field of view, however, it can lead to user confusion about which barcode was actually scanned. Accordingly, a need exists for a mobile device with an improved user interface for code symbol reading.